Also seems serverpilot also integrates ngx_pagespeed https://serverpilot.io/community/articles/how-to-enable-pagespeed.html but you need to ask them what version as 184.108.40.206 and 220.127.116.11+ and soon 18.104.22.168 are latest with security fixes, any older and you have security vulnerabilities. Same can be said for any LEMP or nginx stack which uses ngx_pagespeed and older versions.
Curiosity has me digging and seems they Nginx HTTP/2 implementation doesn't have TLS Extension ALPN support so they must be using TLS Extension NPN with Nginx HTTP/2. So with Chrome ending SPDY support and TLS Extension NPN in May 15th 2016, Chrome browser folks will have issues or fallback to non-HTTP/2 based SSL. FYI, Chrome reports that 99% of HTTP/2 negotiations are already over the new TLS Extension ALPN hence why they're terminating support for older TLS Extension NPN on May 15th, 2016